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Review: ALO RX Amp (Quite Possibly the Perfect JH13 Amp)

post #1 of 106
Thread Starter 
ALO Rx Amplifier – The perfect JH13 amp

The amp is a collaboration between Ken Ball (ALO) and Matt McBeth (GR9). Most people know Ken as the maker of some of the more popular LODs for Ipods and for his recabling of Headphones. Recently Ken took on a venture, starting a retail store largely dedicated to headphone gear, that shows his willingness to take a risk for his passion. Matt is a lesser know commodity here at Head-fi. He attended CanJam 09 at LAX but due to my schedule I was unable to spend any time at his table. I thought he was another crazy guy trying to break into our little hobby with a gimmicky Ipod idea. At RMAF I had the chance to get to know Matt a lot better and my initial impression could not have been more off base. Matt’s been involved as a consultant with several high profile companies including, IEM design, amp manufacturing and Apple Certification. Well after some small talk both Ken and Matt had me check out the Rx amp at their table and I was floored by the sound. What I was hearing was not typical of most portable amps that really color the sound or sound anemic compared to their full sized brethren. After about a half hour of so of listening and chatting I asked Ken and Matt if I could borrow one of the amps for longer term listening and they graciously agreed. Ken outfitted me with one of his cryo docks so I could listen via my Iphone. Ken and Matt were overwhelmed with requests on this amp at RMAF as it was a major hit at the show with many of the IEM manufactures being wowed by its sound.

I have primarily used my Iphone for this review but also used my sonic studio 302 dac/adc just to see how well this portable could scale up. All files used are AIFF, I know to many this is a waste of space on an Iphone. Well I come from a far away time when boys and girls traveled the subways of NYC with a Sony walkman outfitted with improved headphones and 4-6 90 minute TDK or Maxell tapes. The though of having 20-30 albums in my commute bag would have been mind blowing at the time. So I am mainly content to have 12-20 hours of music with me even though I know it is a waste of space in a portable.

Over the course of the month I listened to a wide range of music from old school jazz, punk rock, free jazz, fusion and host of rock titles. For this review though I’ll focus on these titles:
Bill Evans – Waltz for Debby (xrcd)
Van Halen – Van Halen (DCC gold disc)
Pink Floyd – DSOTM (MoFi)
Eric Clapton – Unplugged
Miles Davis – KOB

My primary headphone is the JH13 and most of my non-speaker listening is done on these with some occasional Grado HF-2 thrown into the mix.
Well enough how does the amp sound! First off the Rx is the absolute best portable amp that I have heard with my JH13s and is a contender for top overall amp with these IEMs as I have been on a search for great home amp match as well. I have not owned a tone of portable amps but I have owned the SR 71 (the original one), the Hornet and the Pico. The SR71 and Pico are arguably the two best portables that have been produced and to my mind the Rx sounds better.

With Waltz for Debby the soundstage is spacious left to right and front to back. Some portables do let to right staging well but not so much with front to back this RX nails depth with every recording I threw its way. Waltz for Debby is a great record for sense of space as it captures the crowd noise at the Village Vanguard with a you are there realism. Crowd conversations previously obscured are brought into focus. I am a huge Scott LaFaro fan and his bass sounds amazing with the JH13/ALO Rx combo. I had the pleasure of being present at the Tape Projects mastering session for this LP and heard the master tape through a massive speaker array powered by multiple 300b amps. While certainly massive home sources and amps could better my more humble combo here the sonic signature is very close to my memory of that day. Bass presence and depth that I have rarely heard from this recording, detail like crazy, very dynamic and a sound that is characterized by a fast leading edge. The amp is so clean sounding there is a sense of excitement that I have not felt with my other top end portable amps.

Van Halen ST, Man I love Jamie’s Crying brings me back to the 80s, home of the Camaro with a pioneer tape deck with 6 x 9s pumping out VH! Once again the bottom end is really clean, deeper than a portable rigs has a right to be and super fast. Michael Anthony was never a great bass player but I dug his tone and it is spot on. Guitars are muti-tracked and really shimmer on this track. David Lee Roth and Michael Anthony’s muti-tracked background vocals can be clearly separated and identified (if you wanted to pick the tune apart, mainly I just like to have it flow). Ain’t Talking Bout Love, Dave’s vocals have wonderful reverb and presence. Bass is even better than Jamie’s Crying! Mutitrack guitars are easy to identify and the stereo echo of the opening riff sounds great in all it’s double distorted/flangered glory.

Pink Floyd’s Us and Them of DSOTM was a sonic treat. There is a fair amount of low frequency activity, it’s amazing that IEMs can replicate the punch of a sub in my ear canal. Great punch on this track with this combo, the female singers sound very powerful as well. I’ve listened to this track a lot over the years and this represents some of the best I remember it. Any Color You Like is a great jam instrumental track and the JH13/ALO Rx amp just groove on it. Yeah all the audiophile stuff is there but my overwhelming impression is one of just groove. The interplay of the guitar in the left and right channels at about the half way mark of the song just rocked with great tone and timing. The bottom end on both these tracks are outstanding and not at all what I have ever experienced out of a portable rig. Yeah I’ve heard boomy sloppy out of control bass that overshoots and obscures the mids but not this sound, the sound of a very expensive sub that can scare you with it’s ability to start and stop on a dime.

Eric Clapton’s Old Love from Unplugged is a favorite of mine, for its great song writing, nice piano and guitar solos and general sense of fun the players are having with it. Again I feel like the timing of the JH13/ALO Rx amp is outstanding and it helps to add to the sense of realism. Creating space but also transferring the excitement felt on the recording to the listener. This may have to do with this combos ability to portray the syncopation of the guitars as they create differing rhythms between the left and right channel.

Miles Davis KOB, no matter how many times I spin this record I hear something new or take something different away from it. Flamenco Sketches has such a great feel Miles tone is amazing but the thing I really noticed was his sound as the note begins to build or fade, it creates so much of the emotion of the piece. This combo really brought this out as well as the differences in tone and style that Cannonball and Coltrane brought to the table. Paul Chambers’ does a great job of raising the sense of tension during the second of the sax solos and it’s something that I never noticed much before but this combo really brought this aspect out.

On to the physical nature of the amp, the digital volume control is very well executed with a pressure sensitive toggle switch to raise and lower volume. The form factor is perfect for the iphone, touch and ipod classic user as it is just about the same size as a new Apple Touch. Usually I am not a sucker for the beauty of an amp but Headamp really changed the game for me. My only quibble would be the overall casing of the amp. I'd prefer a more polished look but it still is nice.

While I focused on the JH13s I’ve heard this amp with HD800s. Ultrasone ED9s and Grado HF2s and the sound was no less impressive.

Pros of the ALO Rx in combination with the JH13s are:
Top notch detail without any sense of etch or overly sharp transients
Best in class soundstage, again this really assists with detail
Tone is spot on not overly warm or bright
Bass, best I’ve heard from a portable and maybe from a home amp.
All in all this is a world class portable headphone amp from a sonic perspective.

Battery like not as long as some of the other small amps out there. Hey if you want great sound power is required and it you want a certain form factor something has to give. Still more than enough battery life at 12+ hours.
The casework could be better, while not bad the gold standard has been set by Headamp and it’s the standard that I now judge others by.
My Iphone interferes with the sound unless I pace the phone in airplane mode. This will not be an issue for normal DAPs but may be a consideration for iphone users.

Final Verdict: This is hands down the best portable amp I have heard and I plan on buying one as it is by far the best match for my JH13s. If you are looking for a world class portable that embodies the best qualities of a home amp then you really should take a look at this amp.
post #2 of 106
nice write up. very impressive portable amp.
post #3 of 106
Great Review!!. I am looking for a portable amp to pair with my IE8. I've never been interested in amps to be honest but I'll give this a shot
post #4 of 106
Nice review JP#s! I know you have gone through a lot of gear over the years so your perspective is important and welcome. Thanks.
post #5 of 106
I fully concur. I've had the Rx for only a little while, but already, its 1 ohm output impedance, perfectly balanced attenuator, and dual power source are evident in the music. very, very nice amp which will make the jh13pro work well (not tested yet, but i am assuming!)
post #6 of 106
Thread Starter 
I've also heard it with the hd800, ED9s and HF2s and it sounded great with each of these headphones as well, best I've heard pit of a portable.
post #7 of 106
Great review!
Thanks a lot for taking the time...
post #8 of 106
Very nice review, thanks!

Did you notice any hiss with your JH13s?
Would be great if there's s loaner program. I'm very curious to compare it with my iQube which I also consider the perfect amp for the JH13s
post #9 of 106
Thanks to this review I just ordered the amp. I must admit though I feel so left out not owning the JH 13 hahahaha. Don't worry I'll get there soon enough haha. Thanks again jp11081
post #10 of 106
If it's work for JH13, it must work for UM3, isn't it ?
for the instance my best prortable amp for my UM3 was The Mustang.
(not enough monay for JH 13)
post #11 of 106
2 batteries? I wonder how they managed that... any possibility to get internal pics?
post #12 of 106
let me get my saw out...

Rather not. The only thing which concerns me with the design of the Rx is its input/output which are ringed in plastic rather than metal. I am sure that we will treat our amps well, but there is always the chance that the ports could be damaged.
post #13 of 106
Originally Posted by Lil' Knight View Post
Did you notice any hiss with your JH13s?
I can't comment on the JH13's (they are still on my wish list ), but as for my IEMs (UE5c), the Rx is dead silent.
post #14 of 106
Thread Starter 
Originally Posted by Lil' Knight View Post
Very nice review, thanks!

Did you notice any hiss with your JH13s?
Would be great if there's s loaner program. I'm very curious to compare it with my iQube which I also consider the perfect amp for the JH13s
no hiss with my JH13s, I am willing to bet this will sound better than the mustang for most folks.
post #15 of 106
I will have to listen again with the JH13Pro to make sure about hiss, but it hisses with my my other in ear monitors. That is a caveat with the design for iems.
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